This is a crowded art with much activity in the construction toy system part of it, with many U.S. patents, referred to by number below, known to the inventor which have some pertinence. U.S. Pat. No. 1,113,371 discloses the original rod and hub construction toy system with wooden hubs and rods and with the rod inserted into a hole in the hub and held there by friction and compression (interference fit). U.S. Pat. No. 1,707,691 discloses a hub and rod construction toy system with a hub of stamped metal and wooden rods with slit ends. The connection is formed by inserting the metal hub into the rod-end slit. A great many construction toy systems allow identical elements to be interconnected but with only a few exceptions noted below the actual connections are not genderless. Instead, the male and female connecting elements are placed on opposite ends of the block or hub. In any event, we found no construction system that allowed genderless connection between non-identical elements, e.g., between hub and rod. U.S. Pat. No. 3,626,632 discloses a typical building block system that allows identical blocks to be interconnected by means of a male element on one side and female elements on three other sides. But U.S. Pat. No. 2,800,743 discloses a nearly genderless building block system. But in this system when genderless connections are made the elements are no longer aligned and regular figures can not be constructed. U.S. Pat. No. 2,633,662 discloses a construction toy system with genderless interconnection for hubs connected orthogonally. But hub and rod connections in the same plane are effected with rods that connect across the face of the hubs and do not form a genderless connection. U.S. Pat. No. 4,758,196 discloses a hub and rod construction toy system with genderless rod--rod connections but without any way of directly connecting the hubs.
Various concepts from the construction and other industries have been adapted to construction toy systems. U.S. Pat. No. 3,648,404 discloses a hub and rod construction system designed to be used with hollow rods. The construction toy system disclosed in U.S. Pat. Nos. 4,078,328 and 5,049,105 uses a similar connection system. U.S. Pat. No. 3,891,335 discloses a hub and rod and panel snap together construction system. The hub and rod construction toy system disclosed in U.S. Pat. Nos. 5,061,219, 5,137,486 and 5,199,919 uses a retaining clip similar to the one disclosed in the 335 patent. The 486 patent does disclose a genderless hub--hub connection for orthogonally connecting hubs. However, the means of connecting the hubs is not the same means as connecting rods to hubs.
Other mechanical connectors include U.S. Pat. No. 4,280,339, which discloses a torque transfer device for flexible shaft couplings. Each shaft has an extended portion with forked ends defining teeth. The teeth are inserted orthogonally to each other. U.S. Pat. No. 3,800,556 discloses a power shaft coupling including a coupling mechanism having elongate square bars defining extensions. These extensions may be mutually inserted in orthogonal positional relationship. U.S. Pat. No. 2,577,508 is a universal coupling with bifurcated tongues that mate. U.S. Pat. No. 2,832,943 is a detachable coupling in which the male and female members are not identical but do have an orthogonal insert relationship. U.S. Pat. No. 3,224,222 is a universal joint with yoke members including cross-pintles for connecting the yoke members together.
Hermaphroditic connectors have been used in the electronic connector industry. The invention disclosed herein grew out of our prior electronic connector inventions. See Clever and Lyons U.S. Pat. No. 5,183,409 and continuation in part application Ser. No. 08/011/994.
Other presently known U.S. Patents having interest are: U.S. Pat. Nos. 3,516,043; 3,070,769; 2,690,542; 3,011,143; 4,199,208; 3,634,811; 2,996,026; 3,070,769; 2,475,046; 2,470,282;1,865,300; 2,577,508; 607,607; 3,552,145; 1,171,380; 2,740,271; 4,172,369; 2,460,231; 534,732, and 2,389,115. It is believed that the present invention is patentably distinct from the teachings of any of the above-cited Patents.